Manual proportioning valve question

[Pole120]

I've done away with all the ABS devices on the track car and I'm looking at installing an adjustable proportioning valve to customize brake bias. My question is, do i just run one valve on the rear line only to bring the back half's pressure down, or will both front and rear need valves for adjustment.

[Rara]

You only want to proportion the rear, you want to keep all the front brake. The idea of the prop valve is really to ensure that the rear doesn't lock up before the front.

However, the issue you are now going to find is that because the contour is a diagonal split system, you'll have to install TWO prop valves, one for each rear line, and somehow manage to keep them synchronized.

[Pole120]

You only want to proportion the rear, you want to keep all the front brake. The idea of the prop valve is really to ensure that the rear doesn't lock up before the front.

However, the issue you are now going to find is that because the contour is a diagonal split system, you'll have to install TWO prop valves, one for each rear line, and somehow manage to keep them synchronized.

New lines will be run and it will no longer be diagonal split, should work, no? I have two lines coming off of the Master cylinder, On will feed front lines, the other the rears.

[Rara]

You can make it function, but you are going to have a hard time getting it right I think. Plus, in the event of a circuit failure, you're going to wish you hadn't done it that way. Honestly, if it were me, I'd have left the ABS in and let the EBC do it's thing, and not worry about it. Beyond that, I'd have started over from scratch for a full race car setup.

[Pole120]

I'm open to suggestions on a new setup....

[Rara]

Honestly, I'd revert back to an ABS module from a later car. It would be BIG $$ for you to piece together a better actuation setup. Then just carefully choose your front and rear foundation brake pieces to keep your bias equivalent or very slightly more rear biased than stock. Catch me on AIM or PM me, and we can sort some particular foundation pieces for your needs . . . I'm assuming ultra low cost is still one of your main concerns, lol.

[Pole120]

PMing away.

[bensenvill]

hmm josh, interesting question. I havent put much thought into it for the same reasons Rara mentioned [if I lose brakes, I take a huge preference to just losing 2... hopefully].

anyways I am highly interested in publically hearing more thoughts/developments on this.

I do not have abs on my car [I've even gone so far as grinding the abs mounts off the hub assemblies], I originally had drums and swapped up to disks [courtousy of BLKOUTs demise], and the 260mm front rotors, I would like to be able to experiment with biases.

[Pole120]

Rara and i discussed a lot about both my specific setup and components and getting the proper pieces to complement each other with the stock bias. It seems that keeping the ABS and stock bias control would be my best bet from our talks. I'm undecided as to exactly what the end product will be on my car.

For the sake of information, I've considered posting our conversation.

~Josh

[bensenvill]

yes information, even just for informations sake is a good thing.

anyways I did have a quick question along the lines of this thread. The drum brake cont/cougs have what I've always assumed to be a proportioning valve between the hard and soft lines in the rear wheel well. Now I never put much thought into their exact purpose other than 'universally' was told to leave them be. Would replacing them with an adjustible valve be a viable option [please file that question under the hypothetical realm].